Method and apparatus for predetermining the size of rebored cylinders



E. A. ARP

May 2, 1933.

METHOD AND APPARATUS FOR PREDETERMINING THE SIZE OF REBORED CYLINDERSFiled Nov. 4, 1952 2 Sheets-Sheet l INVENTOR. EWALD AARP A TTORN E YS.

May 2, 1933. E A ARP 1,906,241

METHOD AND APPARATUS FOR PREDETERMINING THE SIZE OF REBORED CYLINDERSFiled Nov. '4, 1952 2 Sheets-Sheet 2 Fig E:

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IN V EN TOR.

EWA w AAR P A TTORNEYS.

Patented May 2, 1933 EWALD A. ARP, OF MINNEAPOLIS, MINNESOTA,

ASSIGNOR TO VAN NORMAN MACHINE TOOL COMPANY, OF SPRINGFIELD,MASSACHUSETTS, A CORPORATION OF MASSA- CHUSETTS METHOD AND APPARATUS FORPREDETERMINING THE SIZE OF REBORED CYLINDERS Application filed November4, 1932. Serial No. 641,212.

This invention relates to the art of boring may in its general featuresbe similar to that cylinders and has particular reference to thereboring of worn cylinders of internal combustion motors. One object ofthe invention is to provide an improved method of predetermining thesize of the rebored cylinder without the necessity of makingmeasurements directly upon the cylinder while it is being machined.Another object is to provide an improved mechanism for facilitating theadjustment of the cutting mechanism while the cutter is removed from theboring device. A further object is to provide an improved method andapparatus by which a cutter can be adjusted under favorable conditionsof light and accessibility to the exact condition necessary to produce arebored cylinder of definitely predetermined size. Further objects ofthe invention will appear from the following description and claims.

The present application is a continuation in part of my priorapplication Serial No. 489,003, filed October 15, 1930.

Referring to the drawings,

Fig. l is a diagrammatic view illustrating the initiation of thereboring operation;

Figs. 2 to 6 inclusive are similar views showing successive stages inthe reboring of the cylinder;

Fig. 6a is a perspective view of a cutting tool and a holder therefor;

Fig. 7 is a section through the cutter and its holder taken on lin770fFig. 8;

Fig. 8 is a section on line 8-8 of Fig. 7;

Fig. 9 is a detail of an adjusting slide;

Fig. 10 is a perspective detail of the tool shank with the adjustingslide removed;

Fig. 11 is a detail of the tool shank and its adjusting slide infixture;

Fig. 12 is a similar view of the adjusting fixture with the tool shankremoved;

Fig. 13 is a section on line 13-13 of Fig. 11; and

Fig. 14 is a sectional plan showing the cutter inserted in a slightlydifferent form of tool holder.

Referring first to Figs. 1 to 6 inclusive, a cylinder block 15 is shownupon which is placed the base 16 of a boring device which position in anadjusting shown in my Patent N 0. 1,868,440 dated July 19, 1932. Thisbase is held to the cylinder block by an anchor 17 preferably of thetype shown in my prior patent. The reboring machine is formed with aguide 20 in which a sleeve 21 is mounted for vertical reciprocation. Atits lower end the sleeve carries a guideor centering head 22 providedwith a circumferential series of radially movable guide fingerswhich'can be controlled in their position by mechanism at the top of themachine as pointed out in my patent referred to. Passing through thesleeve and freely rotatable within it is a cutter shaft 24 carrying atits lower end a cutter head. This cutter head may be circular in form asshown at 25 in Figs. 1 to 6 and 14 or may be rectangular as shown at 25in Figs. 6a, 7 and 8. The sleeve, carrying the rotatable cutter headwith it, can be raised or lowered by a hand lever 26 or automatically bya motor 27 by means of mechanical details which it is not necessary todescribe here.

Before considering the method by which the cylinder is rebored onepreferred con struction of the cutter head will be described withparticular reference to Figs. 6a to 13. In these figures is shown a toolshank 30 having a cutting element 31, usually of tun ten carbide, brazedto it at one end. The s ank is slotted as at 32 and is provided withholes 33 threaded at one side of the slot to receive screws 34, andcountersunk at the other side to receive the screw heads. An adjustingslide 35 is adapted to fit within the slot 32 and is itself slotted at36 to permit the passage of the screws 34. The adjusting slide 35 may bemoved to any desired longitudinal position while the screws 34 areloosened, but upon the tightening of these screws it will be firmlyclamped in position by the drawing together of the two walls of the slot32. The adjusting slide is preferably provided at one end with anabutment 87 having a purpose to be described below.

In Figs. 11, 12 and 13 is shown an adjusting fixture by means of whichthe combined length of the tool shank and the adjusting slide projectingtherefrom can be accurately determined and set. This fixture iscentrally grooved at 41 to form a pocket for the reception of the toolshank, the bottom of the pocket being preferably provided with ribs 42upon which the tool shank rests. At one end the pocket terminates in anabutment 43, against which the cutting point 31 may rest. At the otherend of the fixture a micrometer 44 is secured by a set screw 45. Withthe screws 33 loosened the tool shank is set within the pocket of theadjusting fixture and the micrometer screwed in until the adjustingslide 35 is moved into the desired position as indicated by the readingof the micrometer graduations. The screws 33 are then clamped fixing thecombined length of the tool shank and the adjusting slide at the desiredamount.

The reboring operation will now be considered in detail. The boringdevice is first set upon the cylinder block with the cutter head abovethe cylinder to be rebored. With the cutter shank removed from thecutter head and with the guide fingers 23 retracted the sleeve 21 isfirst lowered into the cylinder as in Fig. 2 and the guide fingersexpanded. W hen all the guide fingers are in contact with the cylinderwall the axis of the cutter shaft is necessarily concentric with thecylinder and the anchor 17 is then tightened to clamp the entirereboring mechanlsm in that position. The combined length of the toolshank and the adjusting slide is now adjusted by the micrometer fixtureuntil the micrometer reading shows the correct amount to give therebored cylinder the size desired and after the screws 33 are clampeddown the tool shank is removed from the fixture and inserted within asocket 46 in the cutter head. The abutment 3? on the adjusting slide mayrest against me bottom of the socket as in Fig. 7 or may rest against anadjusting screw 4'? as in Fig. in either case the abutment formed by theend of the socket or by the end of the set screw may be considered apermanent position at a fixed distance from the axis of the cutter shaft24. The micrometer is preferably graduated so that its reading does notdetermine the length of the cutter shank plus its adjusting slide butshows the radius or diameter of the cylinder to be rebored. In eithercase it will be clear that when the tool shank is once adjusted andplaced within the socket 46 the cutting point will be located with greataccuracy at a predetermined radius from the axis of the shaft. Thisradius is determined by the addition of the distance of the abutmentfrom the axis of the support and the length of the adjusted tool shank.If the socket is radial and does not cross the axis the addition will bearithmetical. If it is radial and does cross the axis the addition isalgebraic. If the socket is not radial the addition is vectorial, thiscase being generic and the two others being special cases under it. iihetool shank may be clamped in the socket as by a set screw 48 bearingupon a strip 49 loosely secured to the socket wall as at 50 or it may bemade a smooth sliding fit in the socket as shown in Fig. 14, thepressure of the cutting operation keeping the tool shank firmly againstthe abutment at the bottom of the socket.

The guide fingers 23 are now retracted, the sleeve 21 raised to carrythe guide fingers and the cutter head clear of the cylinder block andthe adjusted cutter shank inserted as in Fig. 3. It may be pointed outhere that in Figs. 1 to 6 the dimensions of the various parts are verymuch exaggerated in order to give contrast and make the descriptionclear. The cutter shaft is now started into operation and is loweredgradually in the cylinder. Initially the guiding of the cutter head istaken care of by the bearing of the sleeve 21 in the frame of thereboring mechanism. As soon however as a length of out has been takensufficient to bring the guide fingers 23 within the cylinder wall theyare expanded so as to contact with the freshly bored part of thecylinder. During the remainder of the cutting operation the cutter isguided by these fingers (Fig. 5). When the end of the cylinder has beenreached the movement of the parts is stopped, the guide fingersretracted as in Fig. 6, the anchor loosened, the mechanism shifted tobring the cutting point 31 away from the cylinder wall, and the sleeveand cutter head moved back up through the cylinder.

l V hat 1' claim is:

1. A mounting for cutting tools permitting size adjustment of the toolwhile removed from the machine in which it is used, comprising a holderadapted for permanent association with the machine and having apermanently located tool positioning abutment. a tool having a cuttingedge at one end and a fork at the other, a slide frictionally movable inthe fork and having at its end remote from the cutting edge of the toola positionassembled and adjusted tool and slide unit in the holder.

2. A mounting for cutting tools permitting size adjustment of the toolwhile removed from themachine in which it is used, comprising a socketcdholder adapted for permanent association with the machine, the bottom ofthe socket serving as a. permanently located tool positioningadjustment, a tool having a cutting edge at oneend and a fork at theother, a slide frictionally movable in the fork and having at its endremote from the cutting edge of the tool a positioning abutment adaptedfor cooperation with the tool positioning abutment of the holder, meansfor clamping the slide against movement in the fork, a plate in thesocket yieldable towards the tool but restrained against movementlengthwise of the socket, and a clamp screw bearing against said platefor securing the tool firmly within the socket without causingdisplacement of the tool as the screw is being tightened.

3. A precision method of reboring the cylinders of internal combustionmotors and the like to a predetermined size with a boring implement ofthe type having arotatably and axially movable cutter carrier adapted,when the implement is clamped to a cylinder block with the axis of thecutter carrier in accurate alignment with the axis of the cylinder to berebored, to carry a cutting tool in a helical path through saidcylinder; said method comprising ad usting an extensible cutting tool bycalipering while removed from the carrier so as to'fix to apredetermined dimension the distance between the cutting edge of thetool and an abutment contacting portion thereof, and then placing thecutting tool in the cutter carrier with the abutment contacting portionthereof in contact with an abutment on the carrier, the length of thecutting tool from its cutting edge to its abutment contacting portionwhen added vectorially to the distance between the abutment and the axisof rotation of the support giving a distance between the axis of thesupport and the cutting edge of the tool equal to the radius desired forthe finished cylinder, whereby when the tool is rotated and movedaxially through the cylinder with its axis held firmly in alignment withthat of the cylinder the walls of the cylinder will be cut accurately tothe predetermined size for which the cutter was adjusted.

4. In a cylinder reboring machine of the type having a boring barrotatably and longitudinally movable in a base provided with means forclamping it upon an engine block with the axis of the boring bar inalignment with the axis of the cylinder to be rebored; a mounting for aboring tool permitting the reboring of the cylinder to a predetermineddiameter determined by adjustment of the boring tool while removed fromthe cylinder and without direct measurement of the cylinder beingrebored, comprising a holder adapted for permanent association with theboring bar and provided with a tool receiving socket opening laterallyof the boring bar, a tool positioning-abutment located within the socketat a point remote from the o 11 end thereof, a boring tool having acuttlng edge at one end, and a member adjustably secured to the tool andhaving an abutment of less area than the open end of the socket andadapted to contact with the tool positionmg abutment within the socket,-whereby the tool and member may be adjusted when removed from themachine and when inserted in the socket as a unit with the abutments incontact the cutting edge of the tool will be located at a predetermlneddistance from the tool positioning abutment and therefore at apredetermined distance from the axis of the boring bar so that when theboring bar is rotated and advanced through the cylinder the latter willbe'rebored to an exact predetermined diameter.

5. In a cylinder reboring machine of the type having a boring barrotatably and longitudinally movable in a base provided with means forclamping it upon an engine block with the axis of the boring bar inalignment with the axis of the cylinder to be rebored; a mounting for aboring tool permitting the reboring of the cylinder to a predetermineddiameter determined by adjustment of the boring tool while removed fromthe cylinder and without direct measurement of the cylinder beingrebored, comprising a holder adapted for permanent association with theboring bar and provided with a socket opening laterally of the boringbar, a tool positioning abutment located within the socket at a pointremote from the open end thereof, a boring tool having a cutting edge atone end, a member slidably coupled to the tool and having at a pointremote from the cutting edge of the tool an abutment adapted to contactwith the tool positioning abutment of the holder, and means for clampingthe tool and said member in longitudinally adjusted position whileremoved from the holder, whereby the tool and member may be adjusted andclamped when removed from the machine and when inserted in the socket asa unit with the abutments in contactthe cutting edge of the tool will belocated at a predetermined distance from the tool positioning abutmentand therefore at a predetermined distance from the axis of the boringbar so that when the boring bar is rotated and advanced through thecylinder the latter will be rebored to an exact predetermined diameter.

6. In a cylinder reboring machine of the type having a boring barrotatably and longitudinally movable in a base provided with means forclamping it upon an engine block with the axis of the boring bar inalignment with the axis of the cylinder to be rebored; amounting for aboring tool permitting the reboring of the cylinder to a predetermineddiameter determined by adjustment ofthe boring tool while removed fromthe cylinder and without direct measurement of the cylinder beingrebored, comprising a holder adapted for permanent association with theboring bar and provided with a socket opening laterally of the boringbar and having boring tool engaging and confining walls, a toolpositioning abutment located within the socket at a point remote fromthe open end thereof a boring tool having a cutting edge at one end andshaped so as to bear directly against the walls of the socket, so thatthe tool will receive support directly from the holder in all adjustedpositions, and a member adjustably secured to the boring tool and 5having an abutment adapted to contact with the tool positioning abutmentwithin the socket, whereby the tool and member may be adjusted whenremoved from the machine and when inserted in the socket as a unit withthe abutments in contact the cutting edge of the tool will be located ata predetermined distance from the axis of the boring bar so that whenthe boring bar is rotated and advanced through the cylinder the latterwill be rebored to an exact predetermined diameter with the cutting toolsteadied and held directly by the holder.

7 In a cylinder reboring machine of the type having a boring barrotatably and longitudinally movable in a base provided with means forclamping it upon an engine block with the axis of the boring bar inalignment with the axis of the cylinder to be rebored; a mounting for aboring tool permitting the reboring of the cylinder to a predetermineddiameter determined by adjustment of the boring tool while removed fromthe cylinder and without direct measurement of the cylinder beingrebored, comprising a holder adapted for permanent association with theboring bar and provided with a socket opening laterally of the boringbar and having boring tool engaging and confining walls, a toolpositioning abutment located within the socket at a point remote fromthe open end thereof, a boring tool-having a cutting edge at one end andshaped so as to bear directly against the encircling walls of the socketso that the tool will receive support directly from the holder in alladjusted positions, a member slidably coupled to the tool and having ata point remote from the cutting edge of the tool an abument of less areathan the open end of the socket and adapted to contact with the toolpositioning abutment within the socket, and means for clamping the tooland said member in longitudinally adjusted position while removed from.the holder, whereby the tool and said member may be adjusted andclamped when removed from the machine and when inserted in the socket asa unit with the abutments in contact the cutting edge of the tool willbe located at a predetermined distance from the tool positioningabutment and therefore at a predetermined distance from the axis of theboring bar with the cutting tool steadied and held directly by theencircling walls of the holder, so that when the borlng bar is ro- 60tated and advanced through the cylinder the latter will be rebored to anexact predetermined diameter.

In testimony, whereof have affixed my signature.

EWALD A. ARP.

D I SO L.Al M E R 1,906,24L-Ewald A. Arp, Minneapolis, Minn. METHOD ANDAPPARATUS FOR PRE- DETERMINING THE Srzn OF REBORED CYLINDERS. Patentdated May 2, 1933. Disclaimer filed February 13, 1935, by-the assignee,Van Norman Machine Tool Company. Therefore, enters the followingdisclaimer: To the language appearing at page 2, lines 62 to 65 of thespecification of said Letters Patent, to wit: If the socket is notradial the addition is vectorial, this case being generic and the twoothers being special cases under it.

To any method of reboring cylinders as defined in cla1m3 of said LettersPatent except when the adjusted setting of the cutting tool to produce apredetermined size of rebored cylinder is completely and directlydeterminable by calipering the tool along a line substantially in thedirection of extension of the tool whlle the tool-1s removed from thecarrier and when said calipered length is substantially radial withrespect to the axis of rotation of the cutter carrier when the adjustedtool is placed therein.

' To the Word "vectorially appearing in line 21 of claim 3.

To any cylinder reboring machine as defined in c1aims4, 5, 6, and 7 ofsaid Letters Patent except when the socket in the holder issubstantially radial with respect to the axis of rotation of the boringbar and when the adjusted setting of the cutting tool to produce apredetermined size of rebored cylinder is completely and directlydeterminable by calipering the tool and the memberadjustably securedtoit while said tool and member are removed from the machine.

[Ofiicial Gazette March 12, 1985.]

